The field of the disclosure relates generally to systems and methods for polishing metal parts with complex geometries and, more particularly, to a system and method for simultaneous mass finishing and electro-chemical polishing.
Metallic parts made by additive manufacturing and casting require polishing due to the rough surfaces additive manufacturing or casting create. At least some of the known methods for polishing metal parts are mass finishing and electro-chemical polishing. For example, some known mass finishing methods use a flexible media, such as chips or abrasives, to mechanically polish metal parts. Metal parts are placed in a container with flexible media or abrasive surrounding the parts. A vibration mechanism vibrates the container, metal part, and flexible media. The flexible media chips away rough portions of the metal part and produces a metal part with a smooth surface. Mass finishing requires long processing durations to complete a single part.
In addition, some known electro-chemical polishing methods use an electrical circuit, an electrolyte, abrasive particles, and/or a tool. Metal parts are submerged in a container with an electrolyte and abrasive particles. An electrical circuit is formed by connecting the metal part (anode) and the container (cathode) to a power supply. The electrolyte facilitates the flow of electrons from the metal part (anode) to the container (cathode) and completes the circuit. An oxidation reaction occurs between the electrolyte and the metal ions on the surface of the metal part. The oxidation reaction frees a metal ion from the surface of the metal part and frees electrons from the freed metal ions. The free electrons complete the electrical circuit. As metal ions are removed from the metal part surface, the surface becomes smooth. However, the oxidation reaction forms a passive oxide film that prevents unreacted electrolyte from reacting with the fresh surface of the metal part. A passive oxide film removal tool may be used to remove the passive oxide film and promote new oxidation reactions. Some known electro-chemical processes also use abrasive particle particles in the electrolyte in conjunction with a passive oxide film removal tool to promote new oxidation reactions. Electro-chemical polishing has a short processing time to complete a single part. However, because of the need to remove the passive oxide film, electro-chemical polishing is generally limited to polishing metal parts with simple geometries.